U.S. patent number 4,986,534 [Application Number 07/459,970] was granted by the patent office on 1991-01-22 for computerized biomechanical analysis system.
This patent grant is currently assigned to Camp International, Inc.. Invention is credited to Gary W. Gray, Robert H. Meier, Jerry E. Seel.
United States Patent |
4,986,534 |
Meier , et al. |
January 22, 1991 |
Computerized biomechanical analysis system
Abstract
The invention pertains to a method and apparatus for
biomechanically analyzing the physical characteristics of the lower
extremety including hip, knee and ankle joints and the muscles and
ligaments, and the functioning thereof. A frame includes a weight
sensing platform and a foot support in the form of a disc is
mounted above the platform for nutation about a vertical axis. The
periphery of the disc engages the platform, and actuates platform
switches whereby a patient standing upon the disc with one foot may
angularly displace the disc in a nutating manner applying weight to
the platform through the disc periphery, and recording apparatus in
the form of computerized data and a visual display permits analysis
of the application of weight to the platform. The disc may be
selectively vertically adjustable relative to the platform to vary
the analysis characteristics.
Inventors: |
Meier; Robert H. (Ann Arbor,
MI), Seel; Jerry E. (Adrian, MI), Gray; Gary W.
(Adrian, MI) |
Assignee: |
Camp International, Inc.
(Jackson, MI)
|
Family
ID: |
23826893 |
Appl.
No.: |
07/459,970 |
Filed: |
January 2, 1990 |
Current U.S.
Class: |
482/8;
482/902 |
Current CPC
Class: |
A61B
5/1036 (20130101); A61B 5/1107 (20130101); G01G
19/44 (20130101); A61B 5/4528 (20130101); A61B
2505/09 (20130101); Y10S 482/902 (20130101); A61B
2562/0252 (20130101); A61B 2562/046 (20130101) |
Current International
Class: |
A61B
5/11 (20060101); A61B 5/103 (20060101); A61B
5/117 (20060101); G01G 19/44 (20060101); G01G
19/00 (20060101); A63B 023/08 (); A63B 023/10 ();
A63B 022/14 () |
Field of
Search: |
;272/96,70,146,DIG.5
;125/25R,25B ;73/379 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bahr; Robert
Assistant Examiner: Reichard; Lynne A.
Attorney, Agent or Firm: Beaman & Beaman
Claims
We claim:
1. A method of biomechanically analyzing the physical
characteristics of a lower limb comprising the steps of:
(a) placing the foot upon a support capable of universal deviation
about a vertical axis,
(b) sequentially applying weight upon said support at different
angular locations with respect to said axis,
(c) sensing the extent of said weight as applied at said angular
locations to produce a plurality of weight/location values with
respect to said axis, and
(d) recording said values to permit analysis of the distribution of
weight relative to said axis.
2. The method of biomechanical analysis as in claim 1 wherein:
(a) the step of placing the foot upon the support comprising
locating the foot on the support such that the lower leg is
substantially coaxially aligned with said vertical axis.
3. The method of biomechanical analysis as in claim 1 wherein:
(a) the step of sequentially applying weight upon said support
comprises sequentially applying weight in a continuous
unidirectional manner about said vertical axis.
4. The method of biomechanical analysis as in claim 1 wherein:
(a) the step of sensing the extent of said weight comprises
producing an electrical signal, and
(b) the step of recording said values comprises electronically
analyzing and recording said electrical signals.
5. The method of biomechanical analysis as in claim 4, including
the steps of:
(a) producing a visual display of said electrical signals.
6. A method of biomechanically analyzing the physical
characteristics of a lower limb utilizing a support having a center
of nutation comprising the steps of:
(a) placing the foot upon the support in a predetermined position
relative to the center of nutation,
(b) sequentially applying weight upon said support at different
angular locations with respect to said center of nutation,
(c) sensing the extent of said weight as applied at said angular
locations to produce a plurality of weight/location values with
respect to said center of nutation, and
(d) recording said values to permit analysis of the distribution of
weight relative to said center of nutation.
7. The method of biomechanical analysis as in claim 6 wherein:
(a) the step of placing the foot upon the support comprising
locating the foot on the support such that the lower leg is
substantially coaxially aligned with said vertical center of
nutation.
8. The method of biomechanical analysis as in claim 6 wherein:
(a) the step of sequentially applying weight upon said support
comprises sequentially applying weight in a continuous
unidirectional manner about said vertical center of nutation.
9. The method of biomechanical analysis as in claim 6 wherein:
(a) the step of sensing the extent of said weight comprises
producing an electrical signal, and
(b) the step of recording said values comprises electronically
analyzing and recording said electric signals.
10. The method of biomechanical analysis as in claim 9 including
the steps of:
(a) producing a visual display of said electrical signals.
11. A biomechanical analyzing system for the lower limb comprising,
in combination, a frame, a foot support, universal support means
maintaining said foot support upon said frame for universal
movement about a vertical axis, weight sensing means mounted on
said frame sensing the amount of weight imposed by said foot
support on said frame and the angular location of the imposed
weight relative to said axis and having a data output, and
recording means recording said data output to permit the analysis
of weight distribution relative to said axis.
12. In a biomechanical analysis system as in claim 11, said weight
sensing means comprising a platform.
13. In a biomechanical analysis system as in claim 12, said foot
support being mounted above said platform and said universal
support means extending through said platform.
14. In a biomechanical analysis system as in claim 13, said foot
support comprising a disc having a periphery, said platform having
an upper surface disposed toward said disc, a plurality of electric
switches mounted on said platform upper surface adapted to be
selectively engaged and operated by said disc periphery, said
switches being connected to said weight sensing means data
output.
15. In a biomechanical analysis system as in claim 14, said disc
periphery having a non-circular configuration related in shape to
the normal movements of the human ankle.
16. In a biomechanical analysis system as in claim 13, elevator
means supporting said foot support on said frame for adjusting the
vertical position of said foot support and regulating the vertical
spacing between said foot support and said platform.
17. In a biomechanical analysis system as in claim 11, hand hold
means mounted on said frame and vertically extending above said
foot support.
18. A biomechanical analyzing system for the lower limb comprising,
in combination, a frame, a platform, a plurality of spaced
electronic weight sensors mounted on said frame supporting said
platform each having an independent output signal, a vertically
oriented shaft having an axis mounted on said frame having an upper
end extending through and above said platform, a universal joint
mounted on said shaft upper end, a foot support mounted on said
universal joint for universal nutating movement about said axis,
means transferring weight imposed on said foot support in a angular
manner about said axis to said platform, and recording means
sensing said weight sensor output signals, said weight sensors
being angularly related about said shaft axis whereby said
recording means records weight application to said platform about
said axis.
19. In a biomechanical analysis system as in claim 18, said foot
support comprising a disc having a periphery, located above said
platform upon said universal joint said periphery comprising said
means for transferring said weight and adapted to engage said
platform upon said disc nutating about said axis to apply weight
upon said platform about said axis.
20. In a biomechanical analysis system as in claim 19, said disc
periphery having a non-circular configuration related in shape to
the normal movements of the human ankle.
21. In a biomechanical analysis system as in claim 19, a plurality
of electric switches defined on said platform located below said
disc periphery and adapted to be selectively operated by said disc
periphery to indicate the angular orientation of force applied to
said platform relative to said axis, said switches being connected
to said recording means.
22. In a biomechanical analysis system as in claim 19, elevator
means supporting said shaft adapted to selectively vertically
position said shaft, universal joint and foot support relative to
said platform.
23. In a biomechanical analysis system as in claim 18, said
recording means including a computer having an output, and a
cathode ray tube receiving said computer output, said tube visually
indicating the application of weight to said platform relative to
said axis.
24. In a biomechanical analysis system as in claim 18, hand hold
means mounted on said frame and vertically extending above said
foot support.
Description
BACKGROUND OF THE INVENTION
The lower limb functions as an integrated unit during activity, and
in a healthy lower limb the hip, knee, ankles, toes and the
muscles, ligaments and other dynamic functional parts of the lower
limb act as a closed kinetic chain. To return an injured joint to
its previous level of performance it must also perform as an
integrated unit in positions of function while undergoing
rehabilitation. Isolated testing and rehabilitation address only
the isolated injured joint, while the progressive functional
integration of that joint may be even more important than its
isolated condition.
In order to analyze the rehabilitation of a healing lower extremity
joint analysis of the weight distribution of which the foot is
capable of attaining is significant, and devices have been proposed
for such purpose as shown in U.S. Pat. Nos. 2,095,268 and
4,014,398. Exercise devices for the ankle and lower leg are known
as shown in U.S. Pat. No. 4,635,932, and it is known to use
computerized analysis systems for analyzing and recording forces
acting on the human foot, such as shown in U.S. Pat. No. 4,452,447.
However, previously known devices are not of such sophistication
and construction as to provide both functional closed-chain
assessment and rehabilitation of the lower limb and produce
objective data regarding the functional performance of the lower
extremity.
A widely recognized method of closed-chain dynamic rehabilitation
for the lower extremity is the Biomechanical Ankle Platform System
(BAPS), and this device permits rehabilitation of the lower limb as
a unit wherein the lower extremity is able to repair itself in a
functional, integrated manner. The BAPS system is described in U.S.
Pat. No. 4,653,748, and the foot support disc disclosed in this
patent also appears in U.S. Pat. No. Des. 278,924.
It is an object of the invention to provide a biomechanical
analysis system for the lower extremity which permits functional
closed-chain assessment and rehabilitation, and complete readily
analyzable data is instantly produced which permits rapid
evaluation.
A further object of the invention is to provide a method for
biomechanical analysis of the lower limb wherein the method is
based on the principles of dynamic closed chain rehabilitation used
with the BAPS system and wherein rapid assessment of the condition
of the lower extremity is possible and objective data
instantaneously obtained with respect to the analysis.
Yet another object of the invention is to provide a method for
biomechanical analysis of the lower extremity capable of analyzing
the functioning of the lower extremity as a integrated unit while
simultaneously undergoing rehibilitation.
An additional object of the invention is to provide a biomechanical
analysis system for the lower extremity wherein an electronic
assessment output is achieved with the use of the apparatus and an
instant analysis of the functional performance of the extremity is
provided and the patient may view this performancy on a display
screen permitting an immediate visualization of the state of
progress and quantitative analysis.
Another object of the invention is to provide a biomechanical
apparatus for the lower extremity which is easily usable by the
relatively unskilled operator, is easily used by the patient, and
is adjustable though a wide range of operating characteristics to
permit immediate analysis by the patient of his progress.
In the practice of the inventive concepts apparatus is employed
which permits visual and recordable evaluation of the exercising
and rehabilitation when utilizing the BAPS system for lower
extremity rehabilitation. The invention contemplates a method of
lower extremity biomechanical analysis which is immediate and
complete and permits immediate analysis and recognition of various
lower extremity conditions such as equinas, supinatory and
pronatory foot conditions, and permits analysis of pressures of
which the lower limb is capable of exerting anterolaterally,
anteromedially, posterolaterally and posteromedially and the
flexibility of the lower limb and ankle may be immediately
analyzed, for instance, a lack of dorsiflexion may be immediately
discerned. The apparatus permits a more definitive assessment of
the lower extremity than was heretofore available, and with the use
of the invention a more explicit therapy program can be devised
which is more efficient than previously achievable.
The apparatus of the biomechanical analysis system of the invention
includes a frame of a generally rectangularly configuration having
patient hand rails and supports vertically extending thereabove. A
weight sensing platform is mounted upon the frame supported upon a
plurality of accurate, spaced weight measuring sensors whereby the
sensors are capable of accurately determining the presence of
weight as applied to the platform at a given location and produce a
proportional electrical signal.
A vertically extending shaft passes through the platform without
connection thereto, and the upper end of the shaft is provided with
universal joint structure for supporting a foot support disc having
a peripheral configuration similar to that shown in U.S. Pat. No.
4,653,748. This disc includes a configured periphery as described
in the aforementioned patent, and the patient places one foot upon
the disc while grasping the hand holding means above the
platform.
The universal joint support of the disc permits the patient to
nutate the disc about its periphery and apply weight to the
platform through the disc outer periphery at various distances from
the shaft axis as determined by the disc configuration. The upper
surface of the platform includes a plurality of switches sensitive
to engagement by the disc periphery wherein the angular point of
engagement of the disc periphery on the platform may be accurately
electronically determined. Accordingly, by the use of the disc
operated switches and the platform weight sensors the amount of
weight exerted by the patient through the disc upon the platform
may be very accurately located and determined.
The electronic output generated by the platform sensors and the
switches is fed into a computerized system having a software
program capable of analyzing the input and producing an output to a
cathode ray tube (CRT) monitor permitting an immediate visual
observation of the results of the disc movement and weight imposed
upon the disc and platform. This analysis permits various lower
limb conditions to be immediately ascertained, and the program,
when using a color monitor, permits various shades of color to
become visible, the color being proportionate to the amount of
weight being applied to the platform at various angular positions
relative to the shaft axis.
The shaft is supported upon elevator structure which permits the
shaft to be raised and lowered relative to the platform which will
change the angle of operation of the foot supporting disc, i.e. the
higher the disc is above the platform the greater the angle of disc
displacement required to engage the disc periphery with the
platform upper surface. Thus, in initial stages of rehabilitation
the foot supporting disc may be located relatively close to the
platform minimizing the flexing of the ankle and lower extremity
required to engage the disc periphery with the platform. As
rehabilitation progresses, the shaft and disc may be raised further
from the platform to increase the extent of ankle movement
required.
The computerized analysis and output permits instantaneous
visualization of the operation of the biomechanical analysis system
and, of course, by the use of internal memory or use of a printer a
copy of each patient's testing may be readily retained for
comparison with subsequent testing. Depending on whether the
nutation of the foot supporting disc is to be achieved primarily by
ankle movement, or by movement of substantially the whole lower leg
or extremity a wide variety of conditions of the lower extremity
may be readily observed and analyzed, and the practice of the
invention permits complete assessment of the function of the lower
extremity and the patient can be actively involved in his own
rehabilitation and can realize his progress as it occurs. A further
advantage of the invention results from the documentation
achievable with the invention with respect to insurance claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The aforementioned objects and advantages of the invention will be
appreciated from the following description and accompanying
drawings wherein:
FIG. 1 is a front perspective view of a biomechanical analysis
system in accord with the invention illustrating the computer
equipment located adjacent the patient supporting frame
apparatus,
FIG. 2 is a top plan view of the frame of the apparatus,
FIG. 3 is a partial elevational view of the platform and foot
supporting disc, the disc supporting shaft being shown in an
elevated condition,
FIG. 4 is a view similar to FIG. 3, the disc supporting shaft being
shown in a lowered condition,
FIG. 5 is a top plan view of the upper surface of the platform, the
platform covering being removed to illustrate presence of the
switches located therebelow,
FIG. 6 is a perspective view of the underside of the platform,
FIG. 7 is a perspective view of the lower frame, the platform being
removed for purpose of illustration,
FIG. 8 is another perspective view of the lower frame, with the
platform removed, taken from another angle of view,
FIG. 9 is an enlarged elevational view of the shaft and elevator
structure,
FIG. 10 is an enlarged, partial elevational view, partially
sectioned, of the shaft, universal joint and thrust bearing,
FIG. 11 is an enlarged, elevational partially sectional view of the
shaft and elevator structure as taken along section 11--11 of FIG.
9, the universal joint not being illustrated,
FIG. 12 is a schematic illustrative view of a cathode ray display
tube illustrating a typical display of the biomechanical analysis
system in accord with the invention, and
FIG. 13 is a schematic block diagram illustrating the mechanical
and electronic components of the system.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The basic components of apparatus practicing the inventive concepts
is best shown in FIG. 1. The patient supporting apparatus includes
a frame 10 having a weight sensing platform 12 mounted thereon, and
the foot supporting disc 14 is located above the platform in spaced
relationship thereto. A plurality of handrail devices extend
upwardly from the frame about the platform including side rails 16
and vertically extending Y-shaped rails 18 are centrally located so
as to be easily grasped by a patient standing upon the disc 14 with
one foot.
The computerized apparatus associated with the system may be
mounted upon a separate frame 20 and is connected to the electronic
system within the frame by a flexible conductor, not shown. Upon
the frame 20 the computer 22 is mounted which includes a hard disc
memory and a keyboard control 24 is mounted upon frame table 26
while the cathode ray tube (CRT) monitor 28 is mounted upon the
frame table 30 and positioned as to be readily observable by the
patient standing upon the disc 14.
As best illustrated in FIGS. 7 and 8 the frame 10 defines a
rectangular cavity in which the primary mechanical apparatus of the
system of the invention is located. This apparatus includes a
circuit box 32 in which various electronic components such as
relays, printed circuit boards, and the like are located, and the
box includes a removable cover for access. The disc shaft
supporting structure is centrally located as generally represented
at 34, and this structure will be described in greater detail
later.
A platform supporting weight sensing sensor 36 is located a each
interior corner of the frame 10. Each of the four weight sensors 36
includes a vertically extending post 38 for engaging and supporting
the platform 12, and the sensors very accurately determine the
amount of weight imposed upon the sensor and produces an electrical
signal proportional to such weight.
An electric winch motor, generally indicated at 40, is also mounted
within the frame and is mechanically associated with the shaft
support 34 as later described.
The platform 12 is of a generally square configuration having an
upper surface 42 and an under surface 44. The dimensions of the
platform are such that the platform will freely fit within the
inner cavity configuration of the frame 10, and the platform
undersurface includes four pads 46 constituting recesses for
receiving the upper ends of the weight sensor posts 38 wherein the
platform is solely supported on the weight sensor posts in its
normal operating condition. The upper surface 42 of the platform
consists of a flexible covering, such as a thin rubberized sheet,
and a plurality of elongated linear switches 48 are located below
the sheet on the upper side of the platform, such switches being
apparent in FIG. 5. The switches 48 are radially arranged about the
central hole 50 defined through the platform, and the switches are
of such a nature that a vertical force imposed upon a linear switch
will close the switch completing the circuit therethrough. The
underside 44 of the platform 12 is shown in FIG. 6 wherein four
switch connectors 52 are illustrated feeding into the primary
conductor 54 having connector 56 which plugs into electronic
apparatus located within the circuit box 32. Preferably, 120
switches 48 are mounted upon the upper side of the platform 12 each
representing approximately three degrees of angular displacement
about the axis of the hole 50 for a purpose which will be later
appreciated.
The shaft supporting apparatus 34 includes a vertically disposed
shaft 58 located within a tubular sleeve 60. The sleeve includes a
thrust bearing 62, FIG. 10, which supports the enlarged cylindrical
head 64 of the shaft, and the head includes a universal joint or
knuckle 66 which includes pivot axes 68 and 70 disposed at
90.degree. to each other whereby the joint 66 is capable of
rotating toward and away from the viewer, FIG. 10, or to the right
or left, or combinations thereof. The universal joint 66 includes
an upper stud 72 having a radial key 74 extending therefrom and a
shoulder 76 adjacent the key and stud constitutes the support
surface for the foot supporting disc 14 as later described. A
flexible rubber boot 78, FIG. 9, encompasses the universal joint to
protect the same from foreign matter and insure ease of
operation.
The foot supporting disc 14 includes a first side 80 and a second
side 82. These sides are mirror images of each other and each
includes the outline 84 of a footprint so that when the left leg is
being tested side 80 will be disposed upwardly, and visible to the
patient, and when the right leg or extremity is being tested the
disc is assembled to the shaft 58 so that the side 82 is directed
upwardly and visible to the patient. Each of the sides includes a
visible outline of the appropriate foot for designating the
location of the foot during use.
The disc 14 is preferably formed of a synthetic plastic material,
and is usually molded. An insert 86 is molded into the disc having
a cylindrical opening 88 for closely receiving the shaft stud 72,
and a key recess is defined therein whereby the key 74 will
associate with the recess to prevent relative rotation between the
disc and the stud. A hand opening 90 is preferably formed in the
disc for facilitating handling or carrying of the disc.
The periphery 92 of the disc 14 corresponds to the configuration of
the BAPS device disclosed in U.S. Pat. No. 4,653,748. This
non-circular configuration of the disc in conjunction with the
placing of the foot at the indicated position, is correlated to the
computer program so as to permit the desired analysis during
operation. The radial length of the switches 48 with respect to the
platform hole 50 is sufficient to permit the disc periphery 92 to
overlap the switches at all nutating positions of the disc, and it
is to be understood that it is the periphery of the disc 14 which
sequentially operates the switches 48 during analysis, testing and
exercise.
The shaft support structure indicated at 34 includes a framework
94, FIGS. 9 and 11, which includes an upper guide block 96 and a
lower guide block 98. The upper guide block 96 is stationery, and
the sleeve 60 is slidably mounted within a bearing 99 mounted in
block 96. The lower guide block 98 is vertically movable between
the framework columns 100 and is affixed to the lower end of the
sleeve 60 as will be apparent from FIG. 11. The lower guide block
98 is interconnected to upper block 96 by a plurality of
counterbalancing tension springs 102, and the guide block 98 is
raised and lowered through a pair of block and tackle systems which
includes lower pulleys 104 rotatably mounted on the guide block by
shafts 106 located on opposite sides of the sleeve 60. Upper
pulleys 108 are rotatably mounted upon block 96 upon shafts 110 in
alignment with pulleys 104, and each of the pulleys contain a
plurality of grooves for receiving cable 112 which is threaded upon
the pulleys in known block and tackle manner. The end of the cable
112 is anchored to guide block 98 by connector 114, FIG. 9.
Vertical movement of the sleeve 60 and shaft 58 and lower guide
block 98 is sensed by electronic potentiometer 116 which is mounted
on block 98 and operatively connected to a reference cable 118
interposed between the upper and lower regions of the framework 94.
As the lower guide block 98 is raised and lowered the potentiality
pulley 120 associated with the cable 118 rotates producing an
electrical signal by the potentiometer 116 which is fed into the
electronic circuit box 32.
The rotative position of the shaft 58 is also electronically
indicated by an electronic direction indicating sensor device
generally indicated at 122 which is affixed to the lower end of the
shaft 58, FIG. 11. Thus, rotative movement of the shaft 58 will be
sensed by the sensor 122 which will feed an electronic signal into
the box 32 having a value indicating the rotational positon of the
shaft to the frame 10.
Raising and lowering of the guide block 98, sleeve 60, and shaft 58
is accomplished through an electrical winch device generally
indicated at 124. The winch includes the reversible electric motor
40, driving a transmission 126 connected to a drum 128 for
operating the cables 112 associated with each of the block and
tackle systems affixed to the guide blocks. Idler guide pulleys 130
are rotatably mounted upon the upper part of the framework 94 to
prevent chaffing of the cables during operation.
The vertical position of the guide block 98 and shaft 58 will be
determined by how much of the cables 112 is wound upon the winch
drum 128. Rotation of the drum 128 in a direction to wind the
cables thereupon will tension the cables 112 and raise the guide
block 98 through the block and tackle support for the guide block
and shaft. The presence of the counterbalance springs 102, and the
reduction achieved by the transmission 126, and the mechanical
advantage of the block and tackle systems permit a relatively small
electric motor 40 to be used to raise and lower the shaft 58 even
if a patient is standing upon the disc 14.
In use, the operator initially determines the desired vertical
orientation of the disc 14 to the platform 12, and this positioning
of the shaft is achieved by entering the appropriate information
into the computerized system through the keyboard 24. If it is
desired to test the lower extremity for a high degree of
flexibility the shaft 58 will be raised close to its upper limits
by winding a maximum amount of the cables 112 upon the drum 128
wherein the foot supporting disc 14 will be highly elevated as
shown in FIG. 3. If it is desired that a lesser movement of the
ankle and lower extremity occur during testing the winch drum 128
will be unwound to permit the block and tackle devices to lower the
guide plate 98 and lower the shaft 58 and disc 14, as shown in FIG.
4.
The patient places his left or right foot upon the disc 14 upon the
footprint outline 84 indicated thereon, whether the right or left
foot is to be employed is clearly indicated by the configuration of
the footprint outline on the disc. Thereupon, the patient raises
the other leg so that his entire weight is supported upon the disc
14, and the hand rails 18 are grasped to permit the patient to
retain his balance during the testing. Of course, the patient's
weight is not to be applied to the hand rails as such would produce
incorrect readings.
Under instruction from the operator, the patient then begins to
nutate or flex the ankle or lower extremity in a single rotative
direction to progressively and sequentially nutate the disc 14 so
that sequential portions of the disc periphery 92 engage the
platform 12 and actuate sequential switches 48. It will be
appreciated that, normally, at all times, one portion of the disc
periphery 92 will be engaging the platform and that the foot
supporting disc 14, at no time during testing, will be maintained
in a horizontal position so as not to engage the platform except in
a balance test wherein the patient goal is to not touch the edge of
the platform to any switches.
The patient, by the shifting of weight, and flexing of the ankle,
nutates the disc 14 about the axis of the shaft 58, and the axis of
the shaft 58 is preferably, substantially in alignment with the
length of the patient's leg. As the disc 14 nutates different
portions of its periphery 92 will sequentially engage the platform
and sequentially apply pressure to the platform and sequentially
close adjacent switches 48 as the nutation continues. Nutation may
proceed at a relatively rapid rate, i.e. one "revolution" per
second, or may proceed at a slower rate depending on the
capabilities of the patient.
As the weight of the patient is applied to the platform by the disc
periphery 92 the value of such weight will be immediately sensed by
the spaced platform supporting sensors 36. The sensor 36 closest to
the point of engagement of the disc periphery will record the
greatest weight, and as the disc nutates the weight supported by
each of the sensors 36 will rapidly vary, and the output of each of
the sensors is instantaneously fed into the computer 22.
In addition to the platform sensors 36 feeding signals into the
computer, the sequential closing of the switches 48 due to the
pressure of the periphery of the disc also feeds signals into the
computer to accurately determine the location of the forces being
applied to the platform.
During the testing, the program sequentially radially places the
output upon the recording and monitoring equipment in a spiral
manner so that the result has a three-dimensional aspect. For
instance, with respect to FIG. 12, a plurality of substantially
concentric spiral rings 132 are illustrated, each ring
representating a rotation of disc pressure as applied to the
platform 12 and switches 48 by a complete "revolution" of the
nutation movement of the disc 14. Each subsequent disc rotation
produces another ring under the control of the program. Because the
portion of the patient's weight being borne by the shaft 58 and
that being applied to the peripheral disc and platform varies
because of the characteristics of the lower extremity and ankle the
pressure being applied to the platform varies during the
circumference of each circle 132. Preferably, the monitor 28 is of
the color type, and the program produces a different color and hue
of signal in accordance with the pressure being applied to the
platform by the patient. Accordingly, at the end of the test the
plurality of rings 132 will produce a pattern somewhat similar to
that represented in FIG. 12 wherein portions of the pattern will be
of different colors, such as at 134, as compared to other portions
of the pattern, such as at 136, indicating to the observer the
exact ability of the extremity to distribute weight to the platform
at various angular relationships to the axis of the leg. This
information can be compared to "correct" weight distribution of a
normal extremity, and the device of the application produces
instanteously analysis of the condition of the extremity during
testing.
The output of the apparatus of invention may be printed to produce
a hard copy of the results of the testing, and the apparatus, in
addition to be used for testing and analysis, may also be used for
exercise wherein the patient may, during a single use of the
apparatus observe a marked increase in flexibility and a change in
weight distribution, and the operator, by coaching the patient, is
able to advise the patient as to those weight distributions that
are most beneficial and the operator can observe if the patient is
"favoring" the extremity at certain angular orientations
thereof.
Preferably, the computer program permits the monitor to illustrate
a plurality of sequential tests simultaneously to permit the user
to compare consecutive test results and directly observe
improvement or recession of the treatments.
The apparatus of the invention permits a much higher degree of
accuracy in the testing and recording of the analysis of the lower
extremity, and the sensitivity of the apparatus provides
significantly improved assessment procedures over those previously
available.
It is appreciated that various modifications to the inventive
concepts may be apparent to those skilled in the art without
departing from the spirit and scope of the invention.
* * * * *